This chapter is from the book

A Brief History of Fiber-Optic CommunicationsThis section
discusses the history of fiber optics, from the optical semaphore telegraph to
the invention of the first clad glass fiber invented by Abraham Van Heel.
Today more than 80 percent of the world's long-distance voice and data
traffic is carried over optical-fiber cables.

Fiber TypesThis section discusses various multimode and
single-mode fiber types currently used for premise, metro, aerial, submarine,
and long-haul applications.

Fiber-Optic Cable TerminationRemovable and reusable optical
termination in the form of metal and plastic connectors plays a vital role in an
optical system.

SplicingSeamless permanent or semipermanent optical
connections require fibers to be spliced. Fiber-optic cables might have to be
spliced together for a number of reasons.

Physical-Design ConsiderationsWhen designing a fiber-optic
cable plant, you must consider many factors. First and foremost, the designer
must determine whether the cable is to be installed for an inside-plant (ISP) or
outside-plant (OSP) application.

Fiber Span AnalysisOptical loss, or total attenuation, is
the sum of the losses of each individual component between the transmitter
and receiver. Loss-budget analysis is the calculation and verification of a
fiber-optic system's operating characteristics.

A Brief History of Fiber-Optic Communications

Optical communication systems date back to the 1790s, to the optical
semaphore telegraph invented by French inventor Claude Chappe. In 1880,
Alexander Graham Bell patented an optical telephone system, which he called the
Photophone. However, his earlier invention, the telephone, was more practical
and took tangible shape. The Photophone remained an experimental invention and
never materialized. During the 1920s, John Logie Baird in England and Clarence
W. Hansell in the United States patented the idea of using arrays of hollow
pipes or transparent rods to transmit images for television or facsimile
systems.

Abraham Van Heel is also notable for another contribution. Stimulated by a
conversation with the American optical physicist Brian O'Brien, Van Heel
made the crucial innovation of cladding fiber-optic cables. All earlier fibers
developed were bare and lacked any form of cladding, with total internal
reflection occurring at a glass-air interface. Abraham Van Heel covered a bare
fiber or glass or plastic with a transparent cladding of lower refractive index.
This protected the total reflection surface from contamination and greatly
reduced cross talk between fibers. By 1960, glass-clad fibers had attenuation of
about 1 decibel (dB) per meter, fine for medical imaging, but much too high for
communications. In 1961, Elias Snitzer of American Optical published a
theoretical description of a fiber with a core so small it could carry light
with only one waveguide mode. Snitzer's proposal was acceptable for a
medical instrument looking inside the human, but the fiber had a light loss of 1
dB per meter. Communication devices needed to operate over much longer distances
and required a light loss of no more than 10 or 20 dB per kilometer.

By 1964, a critical and theoretical specification was identified by Dr.
Charles K. Kao for long-range communication devices, the 10 or 20 dB of light
loss per kilometer standard. Dr. Kao also illustrated the need for a purer
form of glass to help reduce light loss.

In the summer of 1970, one team of researchers began experimenting with fused
silica, a material capable of extreme purity with a high melting point and a low
refractive index. Corning Glass researchers Robert Maurer, Donald Keck, and
Peter Schultz invented fiber-optic wire or "optical waveguide fibers"
(patent no. 3,711,262), which was capable of carrying 65,000 times more
information than copper wire, through which information carried by a pattern of
light waves could be decoded at a destination even a thousand miles away. The
team had solved the decibel-loss problem presented by Dr. Kao. The team had
developed an SMF with loss of 17 dB/km at 633 nm by doping titanium into the
fiber core. By June of 1972, Robert Maurer, Donald Keck, and Peter Schultz
invented multimode germanium-doped fiber with a loss of 4 dB per kilometer and
much greater strength than titanium-doped fiber. By 1973, John MacChesney
developed a modified chemical vapor-deposition process for fiber manufacture at
Bell Labs. This process spearheaded the commercial manufacture of fiber-optic
cable.

In April 1977, General Telephone and Electronics tested and deployed the
world's first live telephone traffic through a fiber-optic system running
at 6 Mbps, in Long Beach, California. They were soon followed by Bell in May
1977, with an optical telephone communication system installed in the downtown
Chicago area, covering a distance of 1.5 miles (2.4 kilometers). Each
optical-fiber pair carried the equivalent of 672 voice channels and was
equivalent to a DS3 circuit. Today more than 80 percent of the world's
long-distance voice and data traffic is carried over optical-fiber cables.